Biosensor and biosensor manufacturing method

ABSTRACT

A biosensor manufacturing method including a sheet material forming process and a dicing process. In the sheet material forming process a sheet material with plural biosensor forming sections is formed. Each of the biosensor forming sections includes a first base plate, a second base plate stacked on the first base plate and forming a capillary between the second base plate and the leading end portion of the first base plate for sucking in sample liquid, and a hydrophilic layer formed on the second base plate at least in a region facing the capillary. In the dicing process plural biosensors are obtained by dicing the sheet material with a blade from the first base plate side at the leading end of each of the biosensor forming sections, such that the leading end of the capillary opens onto the leading end face of the first base plate and the second base plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/180,016 filed Jul. 11, 2011 which is based on and claims priorityunder 35 USC 119 from Japanese Patent Application No. 2010-158243 filedon Jul. 12, 2010, Japanese Patent Application No. 2011-151428 filed onJul. 8, 2011, and U.S. Provisional Application No. 61/363,467 filed onJul. 12, 2010, which are incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention relates to a biosensor and to a biosensormanufacturing method.

2. Related Art

A biosensor is described in Japanese Patent Application Laid-Open (JP-A)No. 2007-3361 that is configured with a first insulating base plate anda second insulating base plate stuck onto the first insulating baseplate and forming a capillary between the second insulating base plateand a leading end portion of the first insulating base plate for suckingin a sample liquid.

In the field of such types of biosensor a known biosensor manufacturingmethod obtains plural biosensor by dicing a sheet material.Traditionally in such a biosensor manufacturing method a blade isinserted from the second insulating base plate side so as to obtainplural biosensors.

However, in such cases a burr is formed on the second insulating baseplate projecting out towards the capillary side, leading to concern of adrop in capillary sucking ability.

SUMMARY

The present invention is made in consideration of the above issue, andis directed towards a biosensor and biosensor manufacturing methodcapable of securing the sucking ability of the capillary.

A biosensor manufacturing method according to an aspect of the inventionincludes: a sheet material forming process that forms a sheet materialwith a plurality of biosensor forming sections, each of the biosensorforming sections including a first base plate, a second base platestacked on the first base plate and forming a capillary between thesecond base plate and a leading end portion of the first base plate forsucking in sample liquid, and a hydrophilic layer formed on the secondbase plate at least in a region facing the capillary; and a dicingprocess to obtain a plurality of biosensors by dicing the sheet materialwith a blade from the first base plate side at the leading end of eachof the biosensor forming sections, such that a leading end of thecapillary opens onto the leading end face of the first base plate andthe second base plate.

According to the above biosensor manufacturing method, due to the bladebeing inserted from the first base plate side, the opposite side to thesecond base plate formed with the hydrophilic layer, the burr on thesecond base plate induced during dicing can be suppressed fromprojecting out to the hydrophilic layer side. Delamination or damage tothe hydrophilic layer can accordingly be suppressed from occurringduring dicing, and the sucking ability of the capillary can be secured.

In the above biosensor manufacturing method, a first base plate with ahigher toughness than the second base plate may be employed for thefirst base plate in the sheet material forming process.

According to the above biosensor manufacturing method, a first baseplate of higher toughness than the second base plate is employed as thefirst base plate, and hence burring can be suppressed from occurringfrom the first base plate on the capillary side when the blade isinserted from the first base plate side. Obstacles to the sample liquidbeing sucked up by the capillary can be eliminated or reduced, and hencesucking ability of the capillary can be better secured.

However, the leading end portion of the first base plate is deformedtowards the second base plate side when the blade is inserted from thefirst base plate side. Then, when the blade has been removed, theleading end portion of the first base plate returns towards its originalshape. The face on the capillary side of the leading end portion of thefirst base plate accordingly slopes away from the second base plate onprogression towards the leading end. The leading end side of thecapillary is accordingly imparted with a cross-section dimension in thedirection of stacking the first base plate and the second base platethat widens on progression towards the leading end. Consequently, evenwhen the amount of sample liquid is small, for example, the sampleliquid can be readily spotted on the leading end of the capillary, andthe sample liquid can be sucked into the capillary without problems.

In the above biosensor manufacturing method, the leading end of each ofthe biosensor forming sections may be diced so that the leading end faceof the first base plate is a face sloping toward a rear end side of thefirst base plate on progression away from the second base plate.

According to the above biosensor manufacturing method, the leading endface of the first base plate is configured with a face sloping towardsthe rear end side of the first base plate on progression away from thesecond base plate. The sample liquid is hence readily placed in contactwith the hydrophilic layer when the sample liquid is being sucked up bythe capillary, enabling the sample liquid to be sucked up into thecapillary without problems.

In the above biosensor manufacturing method, a single faced blade may beemployed as the blade in the dicing process, the single faced bladeincluding a contact face for contact with the leading end faces of thefirst base plate and the second base plate configured as a face slopingtowards the rear end side of the first base plate on progression fromthe second base plate towards the first base plate side.

According to the above biosensor manufacturing method, a single facedblade is employed with a contact face that makes contact with theleading end faces of the first base plate and the second base plate, andis a face sloping towards the rear end side of the first base plate onprogression from the second base plate side towards the first base plateside. The leading end face of the first base plate can accordingly beplaced after dicing further to the rear end side of the second baseplate than the leading end face of the second base plate, with insertionof the blade also from the first base plate side. Consequently,interference can be suppressed between the holding body holding thesample liquid and the leading end face of the first base plate when thesample liquid is being sucked into the capillary, enabling the sampleliquid to be sucked up into the capillary without problems.

In the above biosensor manufacturing method, a double faced blade may beemployed as the blade in the dicing process, the double faced bladecomprising a pair of blade portions next to each other along an arraydirection of a pair of biosensor forming sections to be diced.

According to the above biosensor manufacturing method, a double facedblade is employed as the blade, and the blade is also inserted from thefirst base plate side. The leading end face of the first base plate canaccordingly be placed after dicing further to the rear end side of thesecond base plate than the leading end face of the second base plate.Consequently, interference can be suppressed between the holding bodyholding the sample liquid and the leading end face of the first baseplate when the sample liquid is being sucked into the capillary,enabling the sample liquid to be sucked up into the capillary withoutproblems.

According to another aspect, a biosensor includes: a first base plate; asecond base plate stacked on the first base plate and forming acapillary between the second base plate and a leading end portion of thefirst base plate that is for sucking in a sample liquid; a hydrophiliclayer formed on the second base plate at least in a region facing thecapillary; and a burr extending out from the second base plate on theside away from the capillary.

According to the above biosensor, the burr is formed on the second baseplate as the first base plate and the second base plate are being dicedby the blade. The burr extends out from the opposite side of the secondbase plate to that of the capillary due to inserting the blade from thefirst base plate side. The burr on the second base plate can accordinglybe suppressed from projecting out to the capillary side of the secondbase plate, this being the hydrophilic layer side. The sucking abilityof the capillary can hence be secured.

In the above biosensor, the first base plate may be formed with highertoughness than the second base plate.

According to the above biosensor the first base plate has highertoughness than the second base plate. Accordingly, generation of a burrfrom the first base plate towards the capillary side can be suppressedwhen the blade is inserted from the first base plate side. Consequently,obstacles to the sample liquid being sucked up by the capillary can beeliminated or reduced. Consequently, sucking ability of the capillarycan be better secured.

In the above biosensor, the leading end side of the capillary may have across-section dimension, in the direction of stacking the first baseplate and the second base plate, which gets wider on progression towardthe leading end.

According to the above biosensor, the cross-section dimension at theleading end side of the capillary in the direction of stacking the firstbase plate and the second base plate widens on progression towards theleading end. Consequently, for example, even if there is only a smallamount of the sample liquid, the sample liquid can be readily spotted onthe leading end of the capillary, and the sample liquid can be suckedinto the capillary without problems.

In the above biosensor, the leading end face of the first base plate maybe formed as a face sloping toward a rear end side of the first baseplate on progression way from the second base plate.

According to the above biosensor, the leading end face of the first baseplate is configured with a face sloping towards the rear end side of thefirst base plate on progression away from the second base plate. Thesample liquid is accordingly readily placed in contact with thehydrophilic layer when the sample liquid is being sucked in by thecapillary, enabling the sample liquid to be sucked up into the capillarywithout problems.

In the above biosensor, the leading end face of the first base plate maybe disposed further to a rear end side of the second base plate than aleading end face of the second base plate.

According to the above biosensor, the leading end face of the first baseplate is placed after dicing further to the rear end side of the secondbase plate than the leading end face of the second base plate.Consequently, interference can accordingly be suppressed between theholding body holding the sample liquid and the leading end face of thefirst base plate when the sample liquid is being sucked into thecapillary, enabling the sample liquid to be sucked up into the capillarywithout problems.

In the above biosensor, a region on the first base plate facing thecapillary may have either a test reagent or an electrode present.

According to the above biosensor, fast mixing of the sample liquid withthe test reagent can be achieved.

In the above biosensor a region of the first base plate facing thecapillary may be also provided with a hydrophilic layer.

According to the above biosensor, the sample liquid arrives faster atthe reaction region, enabling reaction and measurement to beaccomplished in a short period of time.

In the above biosensor blood may be sucked in as the sample liquid.Moreover, the above biosensor may be employed for measuring a bloodsugar value.

The above biosensor sample liquid sucking method may include: spotting asample liquid onto a leading end side of the capillary, such that thesample liquid is caused to creep along a face of the second base plateon a side facing the first base plate, and also caused to creep along aface of the first base plate on a side facing the second base plate.

As explained in detail above, according to the present invention thesuction ability of the capillary can be secured.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is an exploded perspective view of a biosensor according to anexemplary embodiment of the present invention;

FIG. 2 is a cross-section taken on line 2-2 of the biosensor illustratedin FIG. 1;

FIG. 3 is an enlarged cross-section of relevant portions at a leadingend portion of the biosensor illustrated in FIG. 1;

FIG. 4 is an explanatory diagram of the flow of a manufacturing methodfor the biosensor illustrated in FIG. 1;

FIG. 5 is an enlarged diagram of the blade illustrated in FIG. 4;

FIG. 6 is an explanatory diagram of the flow in a modified example of amanufacturing method of the biosensor illustrated in FIG. 1; and

FIG. 7 is an enlarged diagram of the blade illustrated in FIG. 6.

DETAILED DESCRIPTION

Explanation follows regarding an exemplary embodiment of the presentinvention, with reference to the drawings.

A biosensor 10 according to an exemplary embodiment of the presentinvention, illustrated in FIG. 1 and FIG. 2, is, for example, abiosensor employed for taking and analyzing a sample liquid, such asblood. The biosensor 10 includes a first base plate 12, a second baseplate 14, a spacer 16, a resist 18, a carbon electrode 20 and a testreagent 22.

The first base plate 12 and the second base plate 14 are each formed inan elongated rectangular shape, with the first base plate 12 formed withhigher toughness than the second base plate 14. In the present exemplaryembodiment, as an example, the first base plate 12 is formed from astretchable resin film, such as polybutylene terephthalate (PBT). Thesecond base plate 14 is, for example, formed by a resin tape, such aspolyethylene terephthalate (PET). The Izod impact strengths (un-notched)of PBT and PET are 1794 (J/m) and 686 (J/m), respectively. Thus when thefirst base plate 12 is formed from PBT and the second base plate 14 isformed from PET the first base plate 12 has a higher toughness than thesecond base plate 14. A resin material is often employed for thematerial of the first base plate 12 (for example PBT, polyethyleneterephthalate (PET), polycarbonate (PC), or polyvinyl alcohol (PVA)),however there is no limitation thereto. A resin material is oftenemployed for the material of the second base plate 14 (for example PBT,PET, PC, or PVA) however there is no limitation thereto.

A slit 24 is formed at the leading end side of the second base plate 14,extending along the width direction of the second base plate 14. Ahydrophilic layer 26 with hydrophilic properties is formed on the backface of the second base plate 14. The hydrophilic layer 26 may be formedover the entire back face of the second base plate 14, or may be formedlocally in a region facing a capillary 44, described later below. Namelyit is sufficient for the hydrophilic layer 26 to be formed on at leaston a region facing the capillary 44. In the present exemplary embodimentthe hydrophilic layer 26 is formed on the back face of the second baseplate 14. However, configuration may be made with a hydrophilic layerformed on a region of the first base plate 12 facing the second baseplate 14.

The spacer 16 is, for example, formed with double-sided adhesive tapeextending along the second base plate 14. A slit 28 is formed at theleading end side of the spacer 16. The slit 28 is formed extending alongthe width direction of the spacer 16 at a location aligned with the slit24. A cutout 30 is also formed in the spacer 16 further towards theleading end side than the slit 28 and extending along the lengthdirection of the spacer 16. The cutout 30 is employed for configuringthe capillary 44, described later, and is open to the leading end of thespacer 16.

The resist 18 is formed as a protective layer covering the front face ofthe carbon electrode 20. A cutout 32 is formed at the leading end sideof the resist 18 in a location aligned with the above cutout 30. Thecarbon electrode 20 is configured with plural electrodes 34, 36, 38 andwith leads 40, 42.

As shown from top to bottom in FIG. 2, all of the members describedabove are stacked on each other in the sequence of: the second baseplate 14, the spacer 16, the resist 18, the carbon electrode 20, and thefirst base plate 12. When all of the members are stacked together inthis state the capillary 44 is formed between leading end portions ofthe first base plate 12 and the second base plate 14 by the cutout 30.The capillary 44 is open to the leading end faces 12A, 14A of the firstbase plate 12 and the second base plate 14, respectively, and thecapillary 44 also opens to the outside through an air gap 46 formed bythe slits 24, 28.

A portion of each of the electrodes 34, 36, 38 shown in FIG. 1 isexposed through the cutout 32 in the capillary 44, and the test reagent22 is placed in the capillary 44 so as to make contact with a portion ofeach of the electrodes 34, 36, 38. Namely configuration is made suchthat in the region on the first base plate 12 facing the capillary 44either the test reagent 22 or one of the electrodes 34, 36, 38 ispresent.

The biosensor 10 sucks in sample liquid from the leading end of thecapillary 44 by utilizing capillary action and hydrophilic attraction.When the sample liquid is introduced into the capillary 44 a changeoccurs in electrical properties due to a reaction between the sampleliquid and the test reagent 22. In an analysis method using thebiosensor 10 the leads 40, 42 are connected to a measurement instrument,and analysis of the sample liquid is performed by the measurementinstrument detecting such changes in electrical properties.

Explanation follows regarding a manufacturing method for the biosensor10 configured as described above, together with explanation of thecharacteristic configuration of the biosensor 10 achieved using thismanufacturing method.

Namely, in the manufacturing method of the biosensor according to theexemplary embodiment of the present invention, as shown on the left handside of FIG. 4, first a sheet material 62 is formed with pluralbiosensor forming sections 60 that will become the base of the biosensor10 (see FIG. 1). The dotted line L illustrated on the left hand side ofFIG. 4 indicates a boundary between biosensor forming sections 60.

Each of the biosensor forming sections 60 is configured with the firstbase plate 12, the second base plate 14, the spacer 16, the resist 18,the carbon electrode 20 and the test reagent 22, as illustrated inFIG. 1. The first base plate 12 has imparted with higher toughness thanthe second base plate 14 by utilizing materials such as those of theexamples given above. The above processes correspond to the sheetmaterial forming process of the present invention.

The sheet material 62 is then diced. The following processes correspondto the dicing process of the present invention. A fabrication device 70is employed in dicing the sheet material 62, such as the one shown onthe left hand side of FIG. 4. The fabrication device 70 is configuredwith a mold 72 and a single blade 74 formed to the mold 72. The blade 74employs a single face blade, with a contact face 74A that makes contactwith the leading end faces 12A, 14A of the first base plate 12 and thesecond base plate 14. The blade 74 is a face sloping towards the rearend side of the first base plate 12 on progression from the second baseplate 14 side towards the first base plate 12 side. The blade 74 is, asshown in FIG. 5, formed with a face 74B on the opposite side of theblade 74 to the contact face 74A. The face 74B is parallel to the bladeinsertion direction. A reinforcement face 74C is formed at the blade tipside of the contact face 74A. In the present exemplary embodiment theblade tip angles θ1, θ2 of the blade 74 are, for example, formed at 30°.These angles θ may be anything from 5° to 50°, are preferably from 10°to 40°, and are more preferably from 15° to 30°.

As shown at the center and on the right hand side of FIG. 4, the sheetmaterial 62 is diced by the blade 74 at the leading end of each of thebiosensor forming sections 60 from the first base plate 12 side, suchthat the leading end of the capillary 44 is opened to the leading endfaces 12A, 14A of the first base plate 12 and the second base plate 14.

As shown at the center of FIG. 4, the leading end portion 12B of thefirst base plate 12 is deformed towards the second base plate 14 sidewhen the blade 74 is inserted from the first base plate 12 side. Then,when the blade 74 has been removed, as shown on the right hand side ofFIG. 4, the leading end portion 12B of the first base plate 12 returnstowards its original shape. A face 12C is thereby formed on thecapillary 44 side of the leading end portion 12B of the first base plate12. The face 12C slopes away from the second base plate 14 onprogression towards the leading end. The leading end side 44A of thecapillary 44 is accordingly imparted with a cross-section dimension inthe direction of stacking the first base plate 12 and the second baseplate 14 (arrow Y direction) that widens in on progression towards theleading end.

As shown at the center of FIG. 4, the blade 74 is inserted to cut inparallel to the direction of stacking of the first base plate 12 and thesecond base plate 14. The contact face 74A of the blade 74 is a slopingface inclined to the blade insertion direction. The leading end face 12Aof the first base plate 12 after dicing is accordingly formed as asloping face that slopes towards the rear end side of the first baseplate 12 (the arrow B direction in FIG. 3) on progression away from thesecond base plate 14 (the arrow A direction in FIG. 3).

Namely, the leading end of each of the biosensor forming sections 60 isdiced such that the leading end face 12A of the first base plate 12configures a face sloping towards the rear end side of the first baseplate 12 on progression away from the second base plate 14.

Furthermore, as shown on the right hand side of FIG. 4, a burr 48 isformed to the second base plate 14 as the first base plate 12 and thesecond base plate 14 are being diced with the blade 74 from the firstbase plate 12 side. The burr 48 is formed so as to project out towardsthe front in the insertion direction of the blade 74 (the arrow Cdirection side in FIG. 3). Namely, the burr 48 project out from thesecond base plate 14 away from the capillary 44.

By utilizing a single faced blade as described above as the blade 74,after dicing the leading end face 12A of the first base plate 12 ispositioned further to the rear end side of the second base plate 14 thanthe leading end face 14A of the second base plate 14 (the arrow Bdirection side in FIG. 3) when the blade 74 is inserted from the firstbase plate 12 side.

Plural of the biosensors 10 are obtained from the sheet material 62 byperforming the above.

Explanation follows next regarding operation and effect of the exemplaryembodiment of the present invention.

As described in detail above, according to the biosensor manufacturingmethod of the exemplary embodiment of the present invention, byinserting the blade 74 from the first base plate 12 side, this beingopposite side of the second base plate 14 to that formed with thehydrophilic layer 26, the burr on the second base plate 14 inducedduring dicing can be suppressed from projecting out to the hydrophiliclayer 26 side of the second base plate 14. Delamination or damage to thehydrophilic layer 26 can accordingly be suppressed from occurring duringdicing.

Namely, according to the biosensor 10 fabricated by the abovemanufacturing method, the burr 48 is formed on the second base plate 14as the first base plate 12 and the second base plate 14 are being dicedby the blade 74. The burr 48 extends out from the opposite side of thesecond base plate 14 to that of the capillary 44 due to inserting theblade 74 from the first base plate 12 side. The burr 48 of the secondbase plate 14 can accordingly be suppressed from projecting out to thecapillary 44 side of the second base plate 14, this being thehydrophilic layer 26 side. The sucking ability of the capillary 44 canhence be secured.

In this biosensor manufacturing method the first base plate 12 isemployed with higher toughness than the second base plate 14.Accordingly, generation of a burr on the first base plate 12 towards thecapillary 44 side can be suppressed when the blade 74 is inserted fromthe first base plate 12 side. Consequently, according to the biosensor10 fabricated by the above manufacturing method, obstacles to the sampleliquid being sucked up by the capillary 44 can be eliminated or reduced.Consequently, sucking ability of the capillary 44 can be better secured.Occurrences of poor sucking with the biosensor are reduced as follows.The rate of poor sucking occurring is reduced from 42/8000 strips priorto widening structure change to 0/36740 strips after change.

According to the biosensor 10, the cross-section dimension at theleading end side 44A of the capillary 44 in the direction of stackingthe first base plate 12 and the second base plate 14 widens onprogression towards the leading end. Consequently, for example, even ifthere is only a small amount of the sample liquid, the sample liquid canbe readily spotted on the leading end of the capillary 44, and thesample liquid can be sucked into the capillary 44 without problems.

According to the biosensor manufacturing method, the leading end face12A of the first base plate 12 is configured with a face sloping towardsthe rear end side of the first base plate 12 on progression away fromthe second base plate 14. According to the biosensor 10 fabricated bythe above manufacturing method, the sample liquid is readily placed incontact with the hydrophilic layer 26 when the sample liquid is beingsucked up by the capillary 44, enabling the sample liquid to be suckedup into the capillary 44 without problems.

According to the biosensor manufacturing method, by employing a singlefaced blade like the one described above for the blade 74, the leadingend face 12A of the first base plate 12 can be placed after dicingfurther to the rear end side of the second base plate 14 than theleading end face 14A, with insertion of the blade 74 also from the firstbase plate 12 side. Consequently, according to the biosensor 10fabricated by the above manufacturing method, interference can besuppressed between the holding body holding the sample liquid and theleading end face 12A of the first base plate 12 when the sample liquidis being sucked into the capillary 44, enabling the sample liquid to besucked up into the capillary 44 without problems. The holding bodyreferred to here corresponds, for example, to a fingertip when thesample liquid is a drop of blood on a fingertip.

The region of the first base plate 12 facing the capillary 44 isconfigured with either the test reagent 22 or the electrodes 34, 36, 38present, enabling the sample liquid to be speedily mixed with the testreagent 22.

Note that the faces on which the electrodes 34, 36, 38 are placed mayalso be provided with a hydrophilic layer. However, good transportationof the sample liquid is achieved when a hydrophilic layer is formed onthe face opposing the electrodes 34, 36, 38, or on both faces, by makingthe hydrophilicity of the face opposing the electrodes higher. Seedymixing and even mixing with the test reagent 22 is thereby achieved,enabling accurate readings to be made in a short period of time.

A double faced blade 75 may be employed in the dicing process describedabove, as shown in FIG. 6. The blade 75 has a pair of blade portions 76next to each other along the array direction of a pair of biosensorforming sections 60 to be diced (the arrow X direction). As shown inFIG. 7, the blade tip angles θ1, θ2, are, for example, each formed at30°, thereby providing the blade 75 with sloped faces 75A, 75B on bothsides. These angles θ1, θ2 may be anything within the range from 5° to50°, are preferably from 10° to 40°, and more preferably from 15° to30°.

The double faced blade in the present invention is a blade formed withleft-right symmetry in FIG. 6, and the single faced blade in the presentinvention is formed as a blade that is asymmetrical in the left-rightdirection in FIG. 4, with one of its faces configured as a face slopingwith respect to the blade insertion direction.

Also when the blade 75 is inserted from the first base plate 12 side, asshown in FIG. 6, the leading end face 12A of the first base plate 12 canbe positioned further to the rear end side of the second base plate 14than the leading end face 14A of the second base plate 14. Accordinglyinterference between the holding body for holding the sample liquid andthe leading end face 12A of the first base plate 12 when the sampleliquid is being sucked into the capillary 44 can be suppressed, enablingthe sample liquid to be sucked into the capillary 44 without problems.

The blade 74 can employ a single faced blade with its sloping face onthe side facing towards the capillary 44. However, when the blade 75 isemployed the compression load from inserting the blade tip is moreevenly dissipated than when a single faced blade is employed. Thedurability of the blade tip can accordingly be raised, and henceproductivity when using the blade can also be raised. A reduction incost can also be achieved by reducing blade changes caused by blade tipchipping, and by raising the durability of the blade.

The material used for the blade may, as an example be a metal, andtreatment may be performed in order to raise the hardness and durabilityof the blade tip (for example quenching treatment, titanium treatment,diamond treatment), however there is no limitation thereto.

In comparison to processing by knocking out of a mold, the initialinvestment required is reduced since a complicated mold is not required,and the durability of the mold employed can be raised. Each of themanufacturing processes can also be simplified, and since there is noneed to employ a high hardness blade this also enables a reduction incost to be achieved.

By configuration with the hydrophilic layer formed on the first baseplate 12 in the region facing the capillary 44 the sample liquid arrivesat the reaction region faster, enabling reaction and measurement to beaccomplished in a short period of time.

The sample liquid in the present invention includes, for example, a bodyfluid, and in particular blood and urine. Substances to be measuredinclude, for example, substances such as glucose, lactic acid,cholesterol and uric acid. The structure of the above exemplaryembodiment that increases suction force is particularly advantageous forviscous sample liquids in particular, such as blood. Due to the viscousnature of hematocrit and blood corpuscles affecting blood sugarmeasurements the structure of the above exemplary embodiment thatincreases suction force is useful for blood sugar value measurements.

The biosensor 10 of the present exemplary embodiment is preferablyemployed for sucking in blood as the sample liquid, and for measuringblood sugar values. Namely, while generally the viscosity of blood asthe sample liquid can be accommodated, for blood sugar valuemeasurements where there is a requirement for a particularly shortresponse time the shape and characteristics of the biosensor configuredas described above delivers an advantage.

Regarding the sample liquid sucking method of the biosensor 10,preferably the sample liquid is spotted on the leading end side 44A ofthe capillary 44, and the sample liquid is caused to creep along theface of the second base plate 14 on the first base plate 12 side and thesample liquid is also caused to creep along the face of the first baseplate 12 on the second base plate 14 side.

The present invention is explained above by way of exemplaryembodiments, however the present invention is not limited by the above,and obviously various modifications may be implemented within a rangenot departing from the spirit of the invention.

What is claimed is:
 1. A biosensor comprising: a first base plate; asecond base plate stacked on the first base plate and forming acapillary between the second base plate and a leading end portion of thefirst base plate that is for sucking in a sample liquid; a hydrophiliclayer formed on the second base plate at least in a region facing thecapillary; and a projecting portion extending out from the second baseplate on the side away from the capillary.
 2. The biosensor of claim 1,wherein the first base plate is formed with higher toughness than thesecond base plate.
 3. The biosensor of claim 1, wherein the leading endside of the capillary has a cross-section dimension, in the direction ofstacking the first base plate and the second base plate, which getswider on progression toward the leading end.
 4. The biosensor of claim1, wherein the leading end face of the first base plate is formed as aface sloping toward a rear end side of the first base plate onprogression way from the second base plate.
 5. The biosensor of claim 1,wherein the leading end face of the first base plate is disposed furtherto a rear end side of the second base plate than a leading end face ofthe second base plate.
 6. The biosensor of claim 1, wherein a region onthe first base plate facing the capillary has either a test reagent oran electrode present.
 7. The biosensor of claim 1, wherein a region ofthe first base plate facing the capillary is also provided with ahydrophilic layer.
 8. The biosensor of claim 1, wherein blood is suckedin as the sample liquid.
 9. The biosensor of claim 1, wherein thebiosensor is employed for measuring a blood sugar value.
 10. A biosensorsample liquid sucking method in which a sample liquid is sucked in bythe biosensor of claim 6, the biosensor sample liquid sucking methodcomprising: spotting a sample liquid onto a leading end side of thecapillary, such that the sample liquid is caused to creep along a faceof the second base plate on a side facing the first base plate, and alsocaused to creep along a face of the first base plate on a side facingthe second base plate.